mages' blog

Last Friday the Cologne R user group came together for two talks and a quiz at Eye/o, the company behind Adblock Plus, in Köln-Ehrenfeld. Eye/o were a great host, offering nibbles and drinks to warm up the event and pizza at the end.

Cologne R user meeting at Eye/o

The first talk was given by Jiddu Alexander, a physicist turned freelance data scientist. Jiddu gave an introduction into the tidyverse. He presented the concept of tidy data, and how the tidyverse bundle can be used to manage multiple models. Furthermore, he explained the concept of learning curves for model selection. Jiddu's slides are available from his web site.

Jiddu Alexander explaining learning curves

Next up was Nils Glück to share his experience on performance profiling. R code often grows from a small idea for a specific task to a longer and longer script as more and more ideas and use cases are added. Occasionally, we end up with a long and poorly documented script that 'does the job' but has become slow. Finding the bottlenecks and addressing them is good short term remedy. Nils showed us how the Rprof function of the utils package can be used to understand the performance profile of R code. Furthermore, the microbenchmark package with a function of the same name can then be used to test new approaches for a code block.

Nils Glück quoting others who are not bothered about performance

To bridge the time for the pizzas to arrive our host Kirill had prepared a little R quiz: Could we guess the output of simple R statements? Well, it is more difficult than you might think. Kirill had a great selection of quirky one-liners, which he had collected over time and borrowed from the fabulous R Inferno book by Pat Burns.

Next Kölner R meeting

The next meeting will be scheduled in about three months time. Details will be published on our Meetup site. Thanks again to Eye/o for their support.

Please get in touch, if you would like to present at the next meeting.

The 19th Cologne R user group meeting is scheduled for this Friday, 14 October 2016. We have three talks, followed by networking drinks.

• Introduction to the tidyverse tools - Jiddu Alexander
  
• Performance profiling and improvement in R - Nils Glück
  
• Batch processing of R-Scripts with Excel - Klaus Jacobi
  

Venue: Eyeo GmbH, Lichtstraße 25, 50825 Köln

For further details visit our KölnRUG Meetup site.

Notes from past meetings are available here.

Last Thursday the Cologne R user group came together again. This time, our two speakers arrived from Bavaria, to talk about Spark and R Server.

Introduction to Apache Spark

Download slides

Dubravko Dulic gave an introduction to Apache Spark and why Spark might be of interest to data scientists using R. Spark is designed for cluster computing, i.e. to distribute jobs across several computers. Not all tasks in R can be split easily across several nodes in a cluster, but if you use functions like by in R, then it is most likely doable. The by function in R splits a data set into several subsets and applies a specific function to each subgroup and collects the results in the end. In the world of Hadoop, this is called MapReduce. Spark has an advanced DAG (directed acyclic graph) execution engine that supports cyclic data flow and in-memory computing. Additionally, Spark has a direct API for R, which makes it relatively ease to write applications with Spark.

Microsoft R Server

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Since the acquisition of Revolution Analytics in 2015, Microsoft has been busy integrating R into its product offerings. Stefan Cronjaeger gave an overview of how R can be integrated into a production environment. Microsoft R server aims to solve the problem of doing 'big data' analytics with R, which allows to carrying out in-memory and disk-based data analysis. Additional new tools are called ScaleR for big data and parallelized analytics, ConnectR to connect to various other data sources, DistributedR for grid computing. Finally, Stefan showed us how Visual Studio can be used as an R development environment, similar to RStudio.

Next Kölner R meeting

The next meeting will be scheduled in about three months time. Details will be published on our Meetup site. Thanks again to Microsoft for their support.

Please get in touch, if you would like to present at the next meeting.

The 17th Cologne R user group meeting is scheduled for this Friday, 26 February 2016. We have two talks, followed by networking drinks.

• Introduction to Bayesian Regression Models using Stan with the brms package - Paul-Christian Bürkner (Uni Münster)
  
• RKWard: A Graphical User Interface and Integrated Development Environment for Statistical Analysis with R - Meik Michalke (Uni Düsseldorf)
  

Venue: Microsoft Deutschland, Holzmarkt 2a Cologne 50676 DE, Köln

For further details visit our KölnRUG Meetup site. Unfortunately, this event is already fully booked, but please sign up if you would like to come along to future events.

Notes from past meetings are available here.

The 16th Cologne R user group meeting is scheduled for this Friday, 4 December 2015 and we have great line up with three talks followed by networking drinks.

• Monitoring process change using Bayesian methods (Mick Cooney)
  A common business problem is to evaluate the effect of a change of process, and this talk will discuss a straightforward approach to this using conjugate priors.
  
• Editing R files with DataJoy (Dietmar Janetzko)
  Brief introduction to the online collaborative data analysis platform DataJoy.
  
• Emoticons decoder for social media sentiment analysis in R (Jessica Peterka-Bonetta)
  While R seems to be able to display some emoticons properly, many other times it doesn’t, making any further analysis impossible unless you get rid of them. With a little hack, I decoded these emoticons and put them all in a dictionary for further use.
  

Venue: Startplatz, Im Mediapark, 550670 Köln

Drinks and Networking

The event will be followed by drinks (Kölsch!) and networking opportunities.

For further details visit our KölnRUG Meetup site. Please sign up if you would like to come along. Notes from past meetings are available here.

The organisers, Kirill Pomogajko and Markus Gesmann, gratefully acknowledge the sponsorship of Revolution Analytics, who support the Cologne R user group as part of their Matrix programme.

The 15th Cologne R user group meeting is scheduled for this Friday, 18 September 2015 and we have a full agenda with three talks followed by networking drinks.

• R in big data pipeline with luigi (Yuki Katoh)
  R in big data pipeline: Put your awesome R codes into production. Learn how to build solid big data pipeline around it.
  
• shinyjs (Paul Viefers)
  Using JavaScript in shiny, without knowing JavaScript
  
• Experience vs Data (Markus Gesmann)
  How to asses risks with small data sets. Bayesian ideas, belief networks and a small simulation example in Stan/rstan.
  

Please note: Our venue changed! We have outgrown the seminar room at the Institute of Sociology and moved to Startplatz, a start-up incubator venue: Im Mediapark, 550670 Köln

Drinks and Networking

The event will be followed by drinks (Kölsch!) and networking opportunities.

For further details visit our KölnRUG Meetup site. Please sign up if you would like to come along. Notes from past meetings are available here.

The organisers, Kirill Pomogajko and Markus Gesmann, gratefully acknowledge the sponsorship of Revolution Analytics, who support the Cologne R user group as part of their Matrix programme.

The next Cologne R user group meeting is scheduled for this Friday, 6 June 2015 and we have an exciting agenda with two talks followed by networking drinks.

• Data Science at the Commandline (Kirill Pomogajko)
• An Introduction to RStan and the Stan Modelling Language (Paul Viefers)

Please note: Our venue changed! We have outgrown the seminar room at the Institute of Sociology and move to Startplatz, a start-up incubator venue: Im Mediapark, 550670 Köln

Drinks and Networking

The event will be followed by drinks (Kölsch!) and networking opportunities.

For further details visit our KölnRUG Meetup site. Please sign up if you would like to come along. Notes from past meetings are available here.

The organisers, Bernd Weiß and Markus Gesmann, gratefully acknowledge the sponsorship of Revolution Analytics, who support the Cologne R user group as part of their Matrix programme.

The next Cologne R user group meeting is scheduled for this Friday, 6 March 2015 and we have an exciting agenda with two talks, followed by networking drinks:

Using R in Excel via R.NET

Günter Faes and Matthias Spix

MS Office and Excel are the 'de-facto' standards in many industries. Using R with Excel offers an opportunity to combine the statistical power of R with a familiar user interface. R.net offers a user friendly interfaces to Excel; R functions work just like Excel functions and are basically hidden away.

Text Mining with R

Cornelius Puschmann

In addition to the analysis of numerical data, R is increasingly attractive for processing text as well. Cornelius will give a very brief overview of common text mining techniques and their corresponding R implementations, with a focus on useful applications in the social sciences. Techniques will include corpus creation and management (package tm), latent semantic analysis (package lsa), and topic models (package topicmodels), as well as sentiment analysis (experimental package syuzhet). Simple but useful routines such as automatically inferring the language of a text (package text cat , or the gender of a first name (package genderize) will also be briefly pointed out.

Drinks and Networking

The event will be followed by drinks and schnitzel at the Lux.

For further details visit our KölnRUG Meetup site. Please sign up if you would like to come along. Notes from past meetings are available here.

The organisers, Bernd Weiß and Markus Gesmann, gratefully acknowledge the sponsorship of Revolution Analytics, who support the Cologne R user group as part of their Matrix programme.


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The next Cologne R user group meeting is scheduled for this Friday, 12 December 2014.

We have an exciting agenda with two talks on Julia and Dynamic Linear Models:

Introduction to Julia for R Users

Hans Werner Borchers

Julia is a high-performance dynamic programming language for scientific computing, with a syntax that is familiar to users of other technical computing environments (Matlab, Python, R, etc.). It provides a sophisticated compiler, high performance with numerical accuracy, and extensive mathematical function libraries.

Some of the highlights of Julia are an implementation of automated differentiation, an optimisation modelling language, also integrating some of the optimisation solvers available from the COIN-OR project, and user-contributed packages for time series, statistics and machine learning, or operations research.

Dynamic Linear Models and Kalman Filtering

Holger Zien

One of the problems most commonly presented to everybody working in statistics is forecasting time series. The textbook answer is to fit an ARMA model to the data and to use the model for prediction. This approach works well for long and stationary time series. However, often the actual time series one is given to analyse are more complicated. They are ridiculously short and clearly non-stationary. Dynamic Linear Models (DLM) and Kalman Filtering go one step beyond ARMA models and may be applied to these more complicated data. I will give a brief introduction into their mathematical background and will talk about my experience using them in practice.

Drinks and Networking

The event will be followed by drinks and schnitzel at the Lux.

For further details visit our KölnRUG Meetup site. Please sign up if you would like to come along. Notes from past meetings are available here.

The organisers, Bernd Weiß and Markus Gesmann, gratefully acknowledge the sponsorship of Revolution Analytics, who support the Cologne R user group as part of their vector programme.


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The next Cologne R user group meeting is scheduled for this Friday, 12 September 2014.

We have a great agenda with international speakers:

• Maarten-Jan Kallen: Introduction to Renjin, the R interpreter for the JVM
• Jonathan Cornelissen, Martijn Theuwissen: DataCamp - An online interactive learning platform for R

The event will be followed by drinks and schnitzel at the Lux.

The next Cologne R user group meeting is scheduled for this Friday, 23 May 2014.

To celebrate our 10th meeting we welcome:

• Andrie de Vries (Revolution Analytics and Co-author of R for Dummies): Taking R to the Enterprise
• Markus Gesmann: googleVis overview and recent developments

Followed by drinks and schnitzel at the Lux.

Further details available on our KölnRUG Meetup site. Please sign up if you would like to come along. Notes from past meetings are available here.


The organisers, Bernd Weiß and Markus Gesmann, gratefully acknowledge the sponsorship of Revolution Analytics, who support the Cologne R user group as part of their vector programme.


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The next Cologne R user group meeting is scheduled for tomorrow, 26 February 2014. We are delighted to welcome:

• Diego de Castillo: R and databases
• Kim Kuen Tang: Hands on using R and kdb+ together
• Frank Celler: ArangoDB (Lightning Talk)

Further details and the agenda are available on our KölnRUG Meetup site.

Please sign up if you would like to come along. Notes from past meetings are available here.


The organisers, Bernd Weiß and Markus Gesmann, gratefully acknowledge the sponsorship of Revolution Analytics, who support the Cologne R user group as part of their vector programme.


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Quick reminder: The next Cologne R user group meeting is scheduled for this Friday, 13 December 2013. We are delighted to welcome:

• Matt Dowle and Arun Srinivasan: Introduction to data.table
• Thomas Rahlf: Book presentation - Datendesign mit R

Further details and the agenda are available on our KölnRUG Meetup site.

Please sign up if you would like to come along. Notes from past meetings are available here.


The organisers, Bernd Weiß and Markus Gesmann, gratefully acknowledge the sponsorship of Revolution Analytics, who support the Cologne R user group as part of their vector programme.


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Quick reminder: The next Cologne R user group meeting is scheduled for this Friday, 18 October 2013. We will discuss and hear about the apply family of functions and the XLConnect package. Further details and the agenda are available on our KölnRUG Meetup site. Please sign up if you would like to come along. Notes from past meetings are available here.

Thanks to Revolution Analytics, who sponsors the Cologne R user group as part of their vector programme.

Quick reminder: The next Cologne R user group meeting is scheduled for this Friday, 12 April 2013. We will discuss cluster analysis and shiny. Further details and the agenda are available on our KölnRUG Meetup site. Please sign up if you would like to come along. Notes from the last Cologne R user group meeting are available here.

Thanks also to Revolution Analytics, who sponsors the Cologne R user group as part of their vector programme.

Quick reminder: The next Cologne R user group meeting is scheduled for tomorrow, 6 February 2013. All details and the agenda are available on the KölnRUG Meetup site. Please sign up if you would like to come along. Notes from the last Cologne R user group meeting are available here.

Thanks also to Revolution Analytics, who are sponsoring the Cologne R user group as part of their vector programme.

The next Cologne R user group meeting is scheduled for 5 October 2012. All details and the agenda are available on the KölnRUG Meetup site. Please sign up if you would like to come along. Notes from the last Cologne R user group meeting are available here.

Thanks also to Revolution Analytics, who are sponsoring the Cologne R user group as part of their vector programme.

The next Cologne R user group meeting is scheduled for 6 July 2012. All details are available on the new KölnRUG Meetup site. Please sign up if you would like to come along, and notice that there is also pub poll for the after "work" drinks. Notes from the first Cologne R user group meeting are available here.

Venue: Sion em Keldenich, Weyertal 47, 50937 Cologne, Germany, 6 p.m., 30 March 2012,

For more details and registration see the Kölner R User Group page.

Panorama of Cologne by Elke Wetzig. Source: Wikipedia, License: CC-BY-SA